1. Technical Field
This disclosure relates generally to vascular grafts for intraluminal delivery, and in particular, to a method and apparatus for repairing diseased or damaged sections of a vessel by fastening a prosthesis within the vessel.
2. Description of Related Art
Diseased or damaged blood vessels often cause weakening of the vessel wall resulting in an aneurysm whereby a blood vessel and especially an artery have a section of abnormal blood-filled dilation. For example, an abdominal aortic aneurysm is a sac caused by an abnormal dilation of the wall of the aorta, a major artery of the body as it passes through the abdomen.
The abdominal aortic aneurysm usually arises in the infrarenal portion of the arteriosclerotically diseased aorta, for example, below the kidneys. Left untreated, the aneurysm will eventually cause rupture of the sac with ensuing fatal hemorrhaging in a very short time. High mortality associated with rupturing led the state of the art into trans-abdominal surgical repair of abdominal aortic aneurysms.
Surgery involving the abdominal wall, however, is a major undertaking with associated high risks. This type of surgery, in essence, involves replacing the diseased and aneurysmal segment of blood vessel with a prosthetic device which typically is a synthetic tube, or graft, usually fabricated of either DACRON(trademark), TEFLON(trademark), or other suitable material.
The present state of the art for intraluminal repair of a vessel does not fasten a prosthesis to the remaining aortic wall. For example, U.S. Pat. Nos. 5,571,171 and 5,571,173 disclose a method and apparatus for treating an abdominal aortic aneurysm by supplying a prosthesis or an aortic graft for intraluminal delivery that does not fasten the graft to the remaining aortic wall.
Presenting an aortic graft through the aorta by intraluminal delivery avoids major invasive surgery. The ""171 and ""173 patents disclose an aortic graft that is delivered intraluminally to the aneurysm site. The aortic graft is secured to the remaining aortic wall by a balloon that is inflated thereby causing the graft to contact and adhere to the remaining aortic wall.
The major disadvantages related to the combination of endovascular expanders, such as a balloon or stent, and prosthesis is the dilation of the natural artery with consequent migrations and periprosthetic losses. Upon withdrawal of the expander, the tissue is caused to collapse and the prosthesis disengages from the remaining aortic wall and tends to migrate to a location away from the aneurysm site to be repaired. The migration and movement of the disengaged aortic graft would then obstruct the affected vessel. The migration and movement of the aortic graft requires further treatment on the patient to remove the failed attempt to attach the aortic graft to the remaining aortic wall.
Further treatment may include major surgery that is hazardous and traumatic to the patient. Major surgery to remove the aortic graft defeats the benefits of intraluminal delivery of the aortic graft. The current state of the art does not disclose a fastener applicator that intraluminally delivers a vascular graft and endoluminally applies internal fasteners to fasten a prosthesis in place.
Accordingly, there is a present need for a fastener applicator that intraluminally delivers a vascular graft to a site within a vessel and applies fasteners to pass through both a prosthesis and the thickness of a vessel wall. The fastened prosthesis should also have the capability of following dilation of a vessel.
An endovascular fastener applicator for endoluminally delivering protheses for treating a vessel is disclosed. The endovascular fastener applicator includes a delivery assembly and a control assembly. The delivery assembly delivers a graft to a site within a vessel and fastens the prosthesis to a vessel by passing a fastener therethrough. The delivery assembly may include an outer sleeve, delivery tube and drive assembly for fastening a prosthesis to a vessel. The control assembly controls operation of the graft delivery catheter. At least a portion of the applicator can be fabricated from a shape memory material. The applicator can be configured to deploy multiple fasteners.
In one embodiment, an endovascular fastener applicator is provided for endoluminally fastening a prosthetic to a vessel with a fastener, in accordance with the present disclosure. The applicator includes a tubular body that is configured for positioning within a vessel. An expandable portion is disposed adjacent a distal end of the tubular body and is deployable to support a prosthetic in contact with an inner surface of a vessel. A drive assembly is also included for advancing a fastener into the prosthetic. The drive assembly can be coaxially disposed within the tubular body. The drive assembly may include a curved portion oriented at an angle of substantially 90xc2x0 from a longitudinal axis defined by the tubular body. In an alternate embodiment, the drive assembly includes a drive rod having a rectangular cross-section. The drive rod cooperates with an inner diameter of a fastener whereby movement of the drive rod causes advancement of a fastener. The drive assembly may be configured for axial and rotational motion.
The endovascular fastener applicator may include a control assembly that is operatively connected to the drive assembly for extracorporeal control of the applicator. In one embodiment, the control assembly includes a handle having a pistol-grip trigger configuration.
The endovascular fastener applicator may include a delivery tube that is disposed for movement within the tubular body and which defines a channel for movement of the drive assembly therewithin. The delivery tube is configured for advancing a fastener within the tubular body. The delivery tube can be coaxially disposed with the tubular body. In another embodiment, the delivery tube includes an applicator head configured to facilitate deployment of the fastener. The applicator head may have a substantially perpendicular orientation to a longitudinal axis defined by the delivery tube.
The fastener applicator may also include an elongate control positioned for movement within the tubular body. The expandable portion is operatively connected to a distal end of the tubular body and a distal end of the elongate control. The tubular body and the elongate control are manipulable to facilitate support of the prosthetic in contact with an inner surface of a vessel. The elongate control can be coaxially disposed with the tubular body.
The expandable portion may include support members that define open interstitial regions therebetween. The support members can comprise a plurality of flexible wires. The support members may alternatively comprise a plurality of flexible tapes.
In one embodiment, the drive assembly may include at least one fastener guide configured to guide advancement of a fastener. Each fastener guide cooperates with a prosthetic for guiding advancement.
In another alternate embodiment, the applicator head includes an ejection mount that is disposed for movement relative to a prosthetic and configured for deployment of a plurality of helical fasteners. The ejection mount has an ejection head with a saw toothed face which is configured for engaging a prosthetic. A ratchet assembly may be included that is configured to facilitate movement of the ejection mount.
In yet another alternate embodiment, an endovascular fastener applicator system is disclosed for repairing a damaged portion of a vessel. The system includes at least one helical fastener and a prosthetic. Each helical fastener having a penetrating end and a limiting end. An endovascular fastener applicator, as discussed above, is also included. An applicator head, as discussed above, may be included, that is configured for engaging an interior portion of the prosthetic to facilitate uniform deployment of each helical fastener. A drive rod may have a cross-section corresponding to an interior cross-section defined by each helical fastener, and in cooperation, facilitate advancement and deployment of each helical fastener.
In an alternate embodiment, the prosthetic includes an interior band having anchor pads circumferentially spaced about and implanted within the band. The pads correspond to the open interstitial regions of the expandable portion. The drive assembly includes guide wires configured for guiding advancement of each helical fastener and have anchor legs adjacent a distal end of each of the guide wires. The anchor legs releasably engage the anchor pads prior to deployment of each helical fastener and are retractable from the prosthetic upon deployment of each helical fastener.
The applicator head may include an ejection mount configured for deploying at least one helical fastener and movable relative to an interior circumference of the prosthetic for deploying each helical fastener. The ejection mount includes an ejection head having a saw-toothed face for engaging the internal circumference of the prosthetic. The ejection head facilitates uniform deployment of each helical fastener.
A method for endoluminally repairing a damaged portion of a vessel is disclosed.